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WO1996013960A1 - Haut-parleur electrodynamique avec element mobile dans un support fluidique - Google Patents

Haut-parleur electrodynamique avec element mobile dans un support fluidique Download PDF

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Publication number
WO1996013960A1
WO1996013960A1 PCT/DK1995/000429 DK9500429W WO9613960A1 WO 1996013960 A1 WO1996013960 A1 WO 1996013960A1 DK 9500429 W DK9500429 W DK 9500429W WO 9613960 A1 WO9613960 A1 WO 9613960A1
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WO
WIPO (PCT)
Prior art keywords
pole shoes
motion
moving system
axis
magnetic fluid
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Ceased
Application number
PCT/DK1995/000429
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English (en)
Inventor
Dan Kristoffersen
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Individual
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Individual
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Filing date
Publication date
Application filed by Individual filed Critical Individual
Priority to AU38016/95A priority Critical patent/AU3801695A/en
Publication of WO1996013960A1 publication Critical patent/WO1996013960A1/fr
Anticipated expiration legal-status Critical
Ceased legal-status Critical Current

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Classifications

    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04R—LOUDSPEAKERS, MICROPHONES, GRAMOPHONE PICK-UPS OR LIKE ACOUSTIC ELECTROMECHANICAL TRANSDUCERS; DEAF-AID SETS; PUBLIC ADDRESS SYSTEMS
    • H04R9/00—Transducers of moving-coil, moving-strip, or moving-wire type
    • H04R9/02—Details
    • H04R9/025—Magnetic circuit
    • H04R9/027—Air gaps using a magnetic fluid

Definitions

  • the invention relates to an electrodynamic loud ⁇ speaker of the type stated in the introductory part of claim 1.
  • the moving system of such a loudspeaker is ge ⁇ nerally suspended in one or more flexible, mechanical suspensions, of which one is positioned at the edge of the diaphragm.
  • Such suspensions may be produced from impregnated fabric, metal or reinforced or unreinforced plastic or rubber materials.
  • loudspeakers with mechanical suspension are subject to a special kind of distortion due to the inability of these loudspeakers to reproduce signals with a very low volume.
  • This inability is per se difficult to measure in practice, and its influence on the reproduction of mixed signals may generally speaking only be demonstrated by subjective listening tests which require a standard of reference.
  • a certain test may illustrate the phenome ⁇ non, ie. the reproduction by the loudspeaker of a beat on the musical instrument of a triangle the sound of which abates evenly, as it is a well-known fact.
  • DE-2740 661 discloses an electrodynamic loudspea ⁇ ker where the voice coil is guided in an air gap in the magnetic system, and where the air gap is filled with a magnetic fluid. There is thus obtained a damping of the voice coil movement and a significant improvement of the heat dissipation from the voice coil.
  • the sides of the air gap and the sides of the voice coil are designed with smooth surfaces in order to prevent that the magnetic fluid is thrown out of the air gap by large diaphragm fluctuations in a low frequency loudspeaker, without thus reducing the desired acoustic damping.
  • US-4,017,694 discloses a method for damping an electrodynamic loudspeaker by filling the air gap with a non volatile magnetic liquid having a viscosity of 600 to 10,000 centipoises containing from about 4 to about 20% of colloidal magnetic particles.
  • the objects obtained are an improved frequency response, a suppres ⁇ sion of undesired hiss from the loudspeaker and an improvement of the maximum output of a low frequency loudspeaker. It is known eg.
  • loudspeakers are known where the voice coil "floats" in magnetic fluid filled into the air gap formed as a circular cylindrical shell of the loudspeaker. These loudspeakers are produced from known, series production high frequency loudspeakers with the air gap filled with magnetic fluid, and where the movement of the moving system constituted by the voice coil may in a generally known way be controlled by means of a mechanical edge suspension. The production of the experimental loud-speakers is made by removing the edge suspension, and there will then only be the magnetic fluid left for control of the movement of the moving system. Such loudspeakers are described among others in the Danish magazine "High Fidelity" no. 4, 1989 no. 10, 1989 p. 21; and nos. 7-8, 1990 p. 23.
  • these loudspeakers have the dis ⁇ advantage that the magnetic fluid is not retained in a sufficiently effective manner in the air gap, either because, as mentioned, it adheres to the parts of the moving system which are moved outside the air gap, the fluid migrating away from the air gap along the surfaces of the pole shoes or of the voice coil form by a kind of capillary effect, or because drops of the fluid will simply break away by heavy electrical signals.
  • the said capillary effect may eg. appear on unevenly machined surfaces with tool marks. It is further assumed that an inappropriate graduation of the strength of the magnetic field in the peripheral areas may cause a too small withdrawal force on the magnetic fluid which has left the air gap by migration or for another reason.
  • the moving system must be controlled to make a purely linear movement along the axis of motion and must be influenced by a resilient action defining a position of rest in axial direction for the system.
  • the system must thus be secured against capsizing, by which is meant angular deflection between the symmetry axis of the voice coil and the symmetry axis of the pole shoes.
  • the system must further be secured against radial displacement, by which is meant displacement of the axis of the voice coil away from convergence with the symmetry axis of the pole shoes.
  • the system must be secured against rotation arc r.d the axis of motion in order that the flexible lead-;:, wires trans- mitting current from termination fa li ies cr. the body of the loudspeaker to the voice coil are net tightened and thus influence the movement of the moving system.
  • a loudspeaker which is characterised by the features stated in the characterising part of claim 1.
  • a simple and low-cost design of the loudspeaker according to the invention is obtained, magnetic fluid, which is relati ⁇ vely expensive, being positioned in one air gap only.
  • the magnetic fluid serving to obtain an axial resilience is not exposed to hea ir.g from the voice coil whereby the viscosity of the fluid would be affected which would entail a modified spring charac ⁇ teristic.
  • a good stability arair.st capsi- zing of the moving system is obtained as it is supported by the magnetic fluid in two separated a r gaps.
  • the diaphragm in a low frequency loudspeaker may be suspended stably and that at the same time, magnetic fluid is only to be positioned in two air gaps.
  • a desired well-defined position of rest for the moving system is obtained.
  • Fig. 1 shows a longitudinal section in a high frequency loudspeaker according to the invention with the moving system in position
  • Fig. 2 is a section of Fig. 1 showing the means of the loudspeaker for displacing magnetic fluid, on a larger scale
  • Fig. 3 corresponds to Fig. 2 and shows how the means displace magnetic fluid when the moving system is displaced backwards (towards the back of the loud ⁇ speaker)
  • Fig. 4 corresponds to Fig. 2 and 3, and shows how the means displace magnetic fluid when the moving system is displaced forwards (towards the front of the loud ⁇ speaker)
  • Fig. 3 corresponds to Fig. 2 and shows how the means displace magnetic fluid when the moving system is displaced backwards (towards the back of the loud ⁇ speaker)
  • Fig. 4 corresponds to Fig. 2 and 3 and shows how the means displace magnetic fluid when the moving system is displaced forwards (towards the front of the loud ⁇ speaker)
  • Fig. 5 shows means mounted on the voice coil form for displacing magnetic fluid when the moving system is displaced either forwards or backwards or is rotated in one of the rotating directions, seen from the exterior of the voice coil,
  • Fig. 6 shows the means in Fig. 5 seen in the direction of the tangent line of the voice coil form
  • Fig. 7 shows a longitudinal section in a preferred embodiment of a high frequency loudspeaker according to the invention with the moving system removed and without magnetic fluid
  • Fig. 8 shows a longitudinal section of a preferred embodiment of a medium frequency loudspeaker or a low frequency loudspeaker according to the invention with the moving system removed and without magnetic fluid
  • Fig. 9 shows a longitudinal section of the secon ⁇ dary pole shoes and the voice coil form in a preferred embodiment of a loudspeaker according to the invention, on a larger scale.
  • Fig. 1 a high frequency loudspeaker according to the invention.
  • the main elements of the loudspeaker are constituted by a magnetic system and a moving system.
  • the loudspeaker is in the embodiment shown in Fig. 1 rotationally symmetrical about the axis of motion 15 of the moving system.
  • the magnetic system consists of an annular permanent magnet 3 which is rotationally symmetrical around the symmetrical axis 15 of the loudspeaker and magnetized in the direction of this axis.
  • One pole of the magnet is connected to a magnetic yoke 5 on which an inner pole shoe 4, 8 is positioned.
  • the second pole of the magnet is connected to an annular, outer primary pole shoe 1 and an annular, outer secondary pole shoe 12.
  • the magnetic system is joined by glueing.
  • Magnetic fluid 11, 13 is positioned in each air gap 9, 16.
  • the magnetic fluid 13 in the primary gap 9 is divided into a quantity placed between the exterior face of the voice coil 2 and the outer primary pole shoe 1, and a quantity placed between the interior face of the voice coil form 6 and the inner primary pole shoe 4.
  • the magnetic fluid 11 in the secondary air gap 16 is likewise divided into a quantity placed between the outer secondary pole shoe 12 and the exterior face of the voice coil form 6 with the means 10, and a quantity placed between the interior face of the voice coil form 6 and the inner secondary pole shoe 8.
  • the diaphragm 7 is affected by a downward force displacing the moving system such that it capsizes, the voice coil 2 is displaced downwards and the magnetic fluid 13 in the primary air gap 9 is displaced.
  • the fluid is thus displaced from the areas where the magnetic field is most powerful, it tends to move back again and thus tries to bring the voice coil 2 back.
  • the magnetic fluid is displaced mainly in direction of the periphery whereby each of the two quantities of fluid positioned on the outer and inner side, respectively, of the voice coil form will have different layer thickness measured in radial direction.
  • the average power of the magnetic field is higher as the average distance to the pole shoe is smaller and therefore the fluid moves in this direction, thus leading to a uniform layer thickness of the fluid in the entire periphery and on both sides of the voice coil form and thus a centering of this.
  • the used magnetic fluid is preferably a magnetic oil such as Ferrofluid type APG 513 from Ferrofluidics Corporation, Nashua, New Hampshire, USA.
  • This oil is developed for use in a known way in the primary air gap in electrodynamic loudspeakers and it is a very good approximation to a Newtonian liquid which is important in order to avoid acoustic distortion.
  • the moving system is constituted by a voice coil form 6 shaped as a tube section on which a voice coil 2 is coiled opposite the primary air gap 9 and a diaphragm 7 is mounted at the front end. Current is led to the voice coil via not shown lead-in wires from not shown termina ⁇ tion facilities positioned on the body of the loud ⁇ speaker.
  • the moving system may move in the direction of the axis of motion 15.
  • means 10 are fastened to the voice coil form 6 which means displace magnetic oil 11 in the secondary air gap 16 when the moving system is displaced in the longitudinal direc ⁇ tion.
  • the means 10 there may be designed a stop 14 which prevents the moving system 2, 6, 7 from moving unintentionally outside its working area. If, eg. a rather heavy current should be applied to the voice coil or the moving system 2, 6, 7 is in another way exposed to very large stress, the means 10 may be pressed all through the magnetic fluid whereby the moving system comes outside its working area and the loudspeaker ceases to function.
  • Figs. 2-4 are sections on a larger scale of Fig. 1.
  • the moving system 2, 6, 7 is displaced towards the backside of the loudspeaker (to the left in Figs. 1-4) which corresponds to the voice coil 2 being subject to a current in one direction.
  • the front means 10 (the one on the right in Figs. 1-4) is thus dis ⁇ placed into the quantity of magnetic fluid 11 posi ⁇ tioned between the outer secondary pole shoe 12 and the exterior face of the voice coil form 6 with the means 10.
  • a corresponding part of this quantity of magnetic fluid is displaced away from its position of rest against the magnetic attraction which results in a reaction force affecting the front means 10 and trying to press this - and thus the moving system 2, 6, 7 - back to the position of rest.
  • This effect is quite analogous to the buoyancy influencing a body when immersed in a fluid which is affected by gravitation, however, the magnetic attraction affecting the magnetic fluid 11 is not directed in one exact direction, but follows the lines of magnetic force in the secondary air gap 16.
  • Fig. 4 the moving system 2, 6, 7 is displaced in the opposite direction against the front side of the loudspeaker (to the right in Figs. 1-4) corresponding to the voice coil 2 being subject to a current in the other direction.
  • the rear means 10 (the one to the left in Figs. 1-4) is displaced into the magnetic fluid 11 which results in a reaction power influencing this rear means 10 and trying to press the moving system 2, 6, 7 back to the position of rest. In this way, a system with the same effect as a bidirectional spring is established.
  • a preferred embodiment of the means 10 is shown. These are here designated 20 and are in Fig. 5 seen from the exterior side of the voice coil form and in Fig. 6 seen in the direction of the tangent of the voice coil form.
  • the voice coil form is typically provided with several such means, eg. three.
  • the means 20 is - besides being designed to displace magnetic fluid when the moving system is displaced either backwards or forwards - also designed to displace magnetic fluid when the moving system is turned in one of the rotational directions.
  • the means 20 is designed as a thickening of the wall of the voice coil form 6 and runs along a closed curve.
  • the means 20 is defined by an internal limita- tion curve 17 and an external limitation curve 18.
  • the means cooperates with a secondary outer pole shoe 19 corresponding to the pole shoe 12.
  • the active face of the pole shoe 19 facing the voice coil form 6 is concave and formed with a circular cylinder surface corresponding to the run of the voice coil form 6 at a level perpendicular to the axis of motion 15 of the moving system 2, 6, 7.
  • the pole shoe 19 has, seen in the viewing direction of Fig. 5, an extent corresponding to the internal limitation curve 17 of the means 20.
  • the pole shoe 19 and the magnetic fluid 11 are shown in longitudinal section.
  • a preferred embodiment of a high frequency loudspeaker according to the invention is shown with the moving system 2, 6, 7 out of place.
  • the means 10 are here not provided with stops 14 so the moving system may as a matter of course be guided in position when assembling the loudspeaker after the assembling and the magnetization of the magnetic system.
  • the voice coil form 6 is here manufactured from aluminium as it is generally known in the production of loudspeakers and it is therefore designed with a slot 25 in order not to function as a short-circuit turn.
  • the magnetic fluid 11, 13 is injected preferably after magnetization of the magnet and before insertion of the moving system as it would otherwise be difficult to place the fluid in between the internal face of the voice coil form 6 and the inner primary pole shoe 4.
  • the voice coil form 6 is designed with holes such that there is interconnection between the two fluid quantities 11 (Fig. 2) and/or between the two fluid quantities 13 (Fig. 1) on the interior and exterior side, respec ⁇ tively, of the voice coil form 6.
  • connection may be constituted by holes in the voice coil form 6, preferably designed in between the quantities of magnetic fluid 11 as shown in Fig. 2.
  • connection may be constituted by the slot 25 (Fig. 7) .
  • the inner pole shoes 4, 8 are in Fig. 7 designed integrally with the yoke 5 as they have the form of a circumferential projection on a central elongation 21 of the yoke 5.
  • Perforations 22-24 together with the slot 25 serve to prevent airflows from being trapped behind the barriers constituted by magnetic fluid. Such trapped quantities of air may partly, by their heat expansion, displace the magnetic fluid from its position of rest and partly act as an uncontrolled spring for the moving system. Tests have shown that such a trapped resilient quantity of air may have unfortunate acoustic properties.
  • the perforation 22 counterbalan ⁇ ces the alternating pressure occuring behind the diaphragm 7 by the intentional movements hereof, and is designed with wide dimensions in order that the resulting alternating airflow does not give rise to noises.
  • the primary air gap is so narrow that the means 10 cannot pass this, and thus the moving system 2, 6,
  • the voice coil form 6 with the voice coil 2 and the means 10 are brought in position before the outer annular primary pole shoe 1 is mounted on the rest of the magnetic system.
  • magnetic oil is filled into the air gaps, the secondary air gap 16 being accessible through the perforation 23, and the primary air gap 9 being accessible from the front side of the loudspeaker (from the right in Fig. 7) .
  • the diaphragm is mounted on the voice coil form 6.
  • Fig. 8 a preferred embodiment of a low frequen ⁇ cy loudspeaker according to the invention is shown.
  • the non-numbered parts of the figure correspond exactly to the parts shown in Fig. 7.
  • the diaphragm 26 has the form of a rigid conical surface which is firmly connected with the voice coil form 6 and suspended in a yielding manner at its front edge 27.
  • the front suspension may be designed as in generally known low frequency loudspeakers, but is in the shown preferred embodiment designed with magnetic fluid in magnetic fields in secondary air gaps.
  • a front magnetic system 28, 29 is positioned along the front edge 27 of the diaphragm 26 and cooperates with a diaphragm bearing 30 in the form of a short, circular cylindrical tube section which is rigidly connected with the front edge of the diaphragm.
  • FIG. 8 there are shown two alternative designs of the magnetic system 28, 29 for the secondary air gap at the front suspension of the diaphragm.
  • the number 28 refers to an embodiment corresponding to the design of the secondary air gap 16 in the high frequency loudspeakers in Figs. 1 and 7.
  • One or more magnets 31 distributed along the frcr.t edge of a body 32 corresponding to the front edge cf the diaphragm 26 are provided with a circum erential, secondary, inner pole shoe 33 and a circumferential, secondary, outer pole shoe 34 in order to form a secondary air gap 35.
  • the diaphragm bearing 30 is positioned, a not shown quantity of magnetic fluid being positioned between the bearing 30 and each pole shoe
  • the bearing 30 is centred by itself by the already stated effect of the magnetic fluid. As it is shown in a section of Fig. 8, there may on the bearing be positioned means 36 which as to design and effect correspond to the means 10 in Figs. 1 and 7, however, the bearing may also be designed without such means, in that case the necessary restoring force is performed by the means 10.
  • the number 29 refers to an alternative embodiment of the magnetic system for the front suspension of the diaphragm. This alternative embodiment may also be used for the secondary air gap 16 in the high frequency loudspeakers shown in Figs. 1 and 7.
  • One or more magnets 37 distributed along the front edge of a body 32 corresponding to the front edge of the diaphragm 26 are provided with a circum ⁇ ferential, secondary, rear pole shoe 38 and a circum- ferential, secondary, front pole shoe 39 in order to form a secondary air gap 40.
  • the diaphragm bearing 30 is positioned up against this air gap, a not shown quantity of magnetic fluid being positioned between the bearing 30 and the pole shoes 38, 39.
  • the magnetic fluid is thus placed between three circumferential elements, ie. the pole shoes 38, 39 and the bearing 30, and there is only fluid on the exterior of the bearing.
  • the bearing 30 is also here centred by itself by the earlier stated effect of the magnetic fluid.
  • a means 41 whose effect corresponds to that of the means 10 in Figs. 1-4 and 7, but is positioned between the pole shoes 38, 39 such that the thickness of the means increases in the direction away from each pole shoe towards the other pole shoe to a maximum thickness in between the pole shoes.
  • a means 41 designed on the exterior of the bearing 30 has the same effect as the means 10 in Figs. 1-4 and 7 when cooperating with the outer, secondary pole shoe 12.
  • the bearing 30 may also be designed without such an means 41, as mentioned above.
  • the low frequency loudspeakers shown in Fig. 8 has special magnetic systems 28, 29 each with their magnet or set of magnets 31, 37 for secondary air gaps 35, 40
  • the low frequency loudspeakers (Figs. 1, 7) according to the invention may be designed each with their magnet or set of magnets for the primary air gap 9 and the secondary air gap 16, respectively. Corre ⁇ spondingly, this also applies for the part of a lo frequency loudspeaker according to the invention which corresponds to the low frequency loudspeakers in Figs. 1 and 7 and which is seen farthest to the left in Fig. 8.
  • a set of secondary pole shoes 8, 12 in a loudspeaker two arrangements are used to ensure that the oil is retained in the air gap 16.
  • the pole shoes 8, 12 are rotationally symmetrical around the axis of motion 15 of the moving system.
  • the pole shoes 8, 12 are designed with roundings 42, 43 to obtain an essentially even run of the working surfaces of the pole shoes such that local magnetic field concentrations are avoided, which concentrations may occur at pole shoes with more or less sharp edges or corners, as it is known.
  • the object of the embodiment shown in Fig. 9 is a magnetic field which in the direction of the axis of motion 15 decreases evenly in strength in a direction away form the centre of the air gap.
  • the run of the roundings 42, 43 of the pole shoes 8, 12 are preferably designed to obtain a specific, desired graduation of the magnetic field force.
  • a further advantage of this embodiment of the pole shoes 8, 12 is that the flow velocity of the oil in the oscillating movement is reduced substantially when the oil reaches the "trumpet-shaped" mouth constituted by the roundings 42, 43. It is assumed that an uneven graduation of the magnetic field force, which may eg. occur by pole shoes with sharp edges as shown in Figs. 1-4 and 7-8, may partly entail dynamic instability in the fluid when the loudspeaker is influenced by an electrical alternating signal such that the fluid "plashes" or that drops may actually break away, and may partly imply that the field force at a small distance from the air gap is simply too small such that a sufficient, magnetic attraction of the fluid towards the air gap is not maintained.
  • the area of the pole shoes 8, 12 in and close to the air gap 16 is designed with a surface 44 which repels the used magnetic fluid.
  • This fluid repellent surface is preferably procured by means of a coating 44 with a plastic material containing fluo- rine.
  • a suitable coating is eg. the one made by the firm Accoat A/S, Kvistgaard (Denmark) under the designation Accofal 2G. It is a smooth, modified fluorocarbon coating with low friction and good non-stick properties.
  • the film thickness is preferably chosen to be 50 ⁇ m. Even though Fig. 9 only shows coating 44 on the part of the pole shoes 8, 12 which is nearest to the air gap, it will usually be most suitable that the entire part in question is treated, eg. the yoke 5 with the central elongation 21 and the inner pole shoes 4, 8.

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  • Physics & Mathematics (AREA)
  • Engineering & Computer Science (AREA)
  • Acoustics & Sound (AREA)
  • Signal Processing (AREA)
  • Audible-Bandwidth Dynamoelectric Transducers Other Than Pickups (AREA)

Abstract

Dans les haut-parleurs électrodynamiques, l'entrefer primaire (9) dans lequel se trouve la bobine mobile (2) peut être rempli de fluide magnétique afin d'améliorer les propriétés du haut-parleur. Toutefois, les suspensions utilisées dans ces haut-parleurs sont sujettes à de l'hystérésis de friction axiale qui empêche les petits signaux électriques d'être convertis en mouvements de la membrane (7) du haut-parleur. Les propriétés améliorées du haut-parleur ne sont par conséquent pas pleinement utilisées. Selon cette invention, le haut-parleur est doté d'un ou de plusieurs entrefers secondaires (16) dans lequel on place le fluide, et l'élément mobile (2, 6, 7) est pourvu de moyens lui permettant de déplacer le fluide magnétique lorsque l'élément mobile (2, 6, 7) effectue un déplacement dans une direction axiale afin d'obtenir une certaine résilience. Ainsi, l'élément mobile n'est plus soumis à de l'hystérésis frictionnelle, et on parvient en même temps à la stabilité et à la résilience voulues pour empêcher le 'roulis' de l'élément mobile (2, 6, 7).
PCT/DK1995/000429 1994-11-01 1995-10-31 Haut-parleur electrodynamique avec element mobile dans un support fluidique Ceased WO1996013960A1 (fr)

Priority Applications (1)

Application Number Priority Date Filing Date Title
AU38016/95A AU3801695A (en) 1994-11-01 1995-10-31 Electrodynamic loudspeaker with fluid-supported moving system

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DK1264/94 1994-11-01
DK126494A DK171729B1 (da) 1994-11-01 1994-11-01 Elektrodynamisk højttaler med væskeophængt bevægeligt system

Publications (1)

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WO1996013960A1 true WO1996013960A1 (fr) 1996-05-09

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WO (1) WO1996013960A1 (fr)

Cited By (13)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2311438A (en) * 1996-03-21 1997-09-24 Sennheiser Electronic Electrodynamic transducer with a moving coil in a magnetic air gap acoustically sealed by a liquid or solid medium
WO2003086010A1 (fr) * 2002-04-11 2003-10-16 Ferrotec Corporation Micro-haut parleur et son procede d'assemblage
WO2003107718A1 (fr) 2002-06-17 2003-12-24 Ferrotec Corporation Haut parleur audio et son procede d'assemblage
WO2005122636A1 (fr) * 2004-06-03 2005-12-22 Tymphany Corporation Transducteur de suspension magnetique
EP1613126A3 (fr) * 2004-06-21 2006-09-27 Pioneer Corporation Dispositif haut-parleur avec fluide magnétique
FR2919978A1 (fr) * 2007-08-09 2009-02-13 Gilles Milot Transducteur electrodynamique, notamment du type haut-parleur, a suspension ferrofluide et dispositifs associes
WO2010097568A1 (fr) * 2009-02-24 2010-09-02 Armour Home Electronics Ltd Améliorations apportées à des haut-parleurs
CN102884813A (zh) * 2010-01-15 2013-01-16 Phl音响公司 具有浮置悬架和球顶形体的电动换能器
JP2016164949A (ja) * 2015-03-06 2016-09-08 シチズン電子株式会社 振動発生装置および発光装置
JP2016164946A (ja) * 2015-03-06 2016-09-08 シチズン電子株式会社 振動発生装置および発光装置
EP3073763A4 (fr) * 2014-01-28 2017-11-22 Sony Corporation Dispositif de haut-parleur
CN108093353A (zh) * 2017-12-25 2018-05-29 苏州明氏自动化技术有限公司 动铁受话器及其装配方法
CN112312293A (zh) * 2019-07-29 2021-02-02 帝瓦雷公司 低惯性扬声器

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN114786113A (zh) * 2022-04-21 2022-07-22 深圳市冠旭电子股份有限公司 一种扬声器和扬声设备

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Publication number Priority date Publication date Assignee Title
DE2604888A1 (de) * 1975-02-10 1976-08-19 Ard Anstalt Lautsprecher
US4017694A (en) * 1976-02-18 1977-04-12 Essex Group, Inc. Method for making loudspeaker with magnetic fluid enveloping the voice coil
US4235302A (en) * 1977-03-15 1980-11-25 Kenkichi Tsukamoto Loudspeaker
DE3241898A1 (de) * 1982-11-12 1984-07-19 Telefunken Fernseh Und Rundfunk Gmbh, 3000 Hannover Elektrodynamischer wandler

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE2604888A1 (de) * 1975-02-10 1976-08-19 Ard Anstalt Lautsprecher
US4017694A (en) * 1976-02-18 1977-04-12 Essex Group, Inc. Method for making loudspeaker with magnetic fluid enveloping the voice coil
US4235302A (en) * 1977-03-15 1980-11-25 Kenkichi Tsukamoto Loudspeaker
DE3241898A1 (de) * 1982-11-12 1984-07-19 Telefunken Fernseh Und Rundfunk Gmbh, 3000 Hannover Elektrodynamischer wandler

Cited By (28)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2311438B (en) * 1996-03-21 2000-02-23 Sennheiser Electronic Electrodynamic acoustic transducer with magnetic gap sealing
US6208743B1 (en) 1996-03-21 2001-03-27 Sennheiser Electronic Gmbh & Co. K.G. Electrodynamic acoustic transducer with magnetic gap sealing
GB2311438A (en) * 1996-03-21 1997-09-24 Sennheiser Electronic Electrodynamic transducer with a moving coil in a magnetic air gap acoustically sealed by a liquid or solid medium
WO2003086010A1 (fr) * 2002-04-11 2003-10-16 Ferrotec Corporation Micro-haut parleur et son procede d'assemblage
EP1576850B1 (fr) * 2002-06-17 2012-05-02 Ferrotec Corporation Haut parleur audio et son procede d'assemblage
WO2003107718A1 (fr) 2002-06-17 2003-12-24 Ferrotec Corporation Haut parleur audio et son procede d'assemblage
WO2005122636A1 (fr) * 2004-06-03 2005-12-22 Tymphany Corporation Transducteur de suspension magnetique
US9301034B2 (en) 2004-06-03 2016-03-29 Tymphany Worldwide Enterprises Limited Magnetic suspension transducer
EP1613126A3 (fr) * 2004-06-21 2006-09-27 Pioneer Corporation Dispositif haut-parleur avec fluide magnétique
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JP2016164949A (ja) * 2015-03-06 2016-09-08 シチズン電子株式会社 振動発生装置および発光装置
JP2016164946A (ja) * 2015-03-06 2016-09-08 シチズン電子株式会社 振動発生装置および発光装置
CN108093353A (zh) * 2017-12-25 2018-05-29 苏州明氏自动化技术有限公司 动铁受话器及其装配方法
CN108093353B (zh) * 2017-12-25 2024-05-31 苏州格洛佛精密科技有限公司 动铁受话器及其装配方法
CN112312293A (zh) * 2019-07-29 2021-02-02 帝瓦雷公司 低惯性扬声器
EP3772225A1 (fr) * 2019-07-29 2021-02-03 Devialet Haut-parleur à faible inertie
FR3099677A1 (fr) * 2019-07-29 2021-02-05 Devialet Haut-parleur à faible inertie
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AU3801695A (en) 1996-05-23
DK171729B1 (da) 1997-04-14
DK126494A (da) 1996-05-02

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